The effect of solid on the homogenous-heterogeneous transition region in baffled and unbaffled bubble column with non-Newtonian liquid

الملخص EN

This research shows a comprehensive study on the effect of solid loading and non-Newtonian liquid on the hydrodynamic parameter of gas holdup as well as the critical values of gas holdup and gas velocity of transition zone from homogenous to heterogeneous region in both baffled and unbaffled babble column.

The experiments were carried out using column of 15cm inside diameter and 2m height with aspect ratio (L/D=4.5) using perforated plate gas sparger 54 holes with size equal to 1mm diameter and with free area of holes to cross sectional area of column 0.24.

The three phase system consists of air-non Newtonian liquid of polyacrilamined (PAA) –solid of alumina particles.

The measured values of gas holdup and transition points of gas holdup and gas velocity were compared with different values of PAA concentration (0, 0.01, 0.05 and 0.1)wt% and four values of solid loading (0, 3, 5 and 11)wt% in baffled and unbaffled column.

The results show that the transition values of gas holdup and gas velocity decreased with increasing of PAA concentration under constant values of Newtonian liquid while they dis approved with non-Newtonian liquid.

The solid loading shows an unstable influence of decreasing and increasing of the critical values in all PAA concentration and in both baffled and unbaffled column.

First, these values decreased when solid loading in the range (0-3)wt% then they increased with increasing of solid loading from 3wt% to 11wt%.